Fuel Gauge Always Shows "Full": Troubleshooting

Hello everyone.

Unfortunately, I don't have a diagnostic tool yet... BUT this problem is definitely not happening for the first time on my Audi A6 2000, 2.5lt quattro AKE, with 210,000 km. The fuel gauge always stays at full while driving. When I turn off the ignition, it normally goes to zero. Where should I start looking?

Where should we look? Right, at the fuel level sensor.

The behavior of the gauge is perfectly normal when the tank is full.
When the tank is full, the sender is at the top.

If it gets stuck now, the needle will always show full and will obediently return to its resting position when the ignition is switched off.

Therefore, I think the giver is a bit strange.

Or what does the needle do when you disconnect the wires from the sensor?

m,

I also think it's the fuel sensor. What else could it be? The needle going to zero when you turn off the ignition is probably normal... (or at least it should be.) *g*

Thank you for your help. I disconnected the fuel level sensor, but the fuel gauge still shows full. I'll try replacing the sensor next week.

Thank you for your help. I disconnected the fuel level sensor, but the fuel gauge still shows full. I will try replacing the fuel level sensor next week.
If you disconnect the cable from the fuel level sensor, the needle should normally go to zero. If you connect the cable to ground, it should rise.
If this is not the case, the fuel level sensor is functioning correctly.

Cormack wrote:

Thank you for your help. I disconnected the fuel level sensor, but the fuel gauge still shows full. I will try replacing the fuel level sensor next week.

You probably have a cable break between the fuel gauge and the sender. Or a short circuit - I don't know if your sender provides the highest or lowest resistance when the tank is full.